New Zealand Police said they would remain highly vigilant and highly present across the country after an attack that killed 49 people and wounded dozens, prompting the prime minister to vow reform of the country's gun laws.

ROUGH CUT - NO REPORTER NARRATION New Zealand Police said they would remain highly vigilant and highly present across the country on Saturday (March 16) after an attack that killed 49 people and wounded dozens, prompting the prime minister to vow reform of the country's gun laws.

Brenton Harrison Tarrant, a 28-year-old Australian citizen, appeared earlier in a Christchurch District Court on Saturday and was remanded without a plea until his next scheduled appearance in the South Island city's High Court on April 5.

The attack, which Prime Minister Jacinda Ardern labelled as terrorism, was the worst ever peacetime mass killing in New Zealand and the country raised its security threat level to the highest.